supersize: Add "diff" command

tools/binary_size/libsupersize/paths.py

 # Copyright 2017 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Functions for dealing with determining --tool-prefix."""
 
 import distutils.spawn
 import logging
 import os
 
 _STATUS_DETECTED = 1
 _STATUS_VERIFIED = 2
 
 
 class LazyPaths(object):
-  def __init__(self, args=None, tool_prefix=None, output_directory=None,
-               input_file=None):
-    tool_prefix = tool_prefix or (args and args.tool_prefix)
-    output_directory = output_directory or (args and args.output_directory)
+  def __init__(self, tool_prefix=None, output_directory=None,
+               any_path_within_output_directory=None):
     self._tool_prefix = tool_prefix
     self._output_directory = output_directory
-    self._input_file = input_file
+    self._any_path_within_output_directory = any_path_within_output_directory
     self._output_directory_status = _STATUS_DETECTED if output_directory else 0
     self._tool_prefix_status = _STATUS_DETECTED if tool_prefix else 0
 
   @property
   def tool_prefix(self):
     if self._tool_prefix_status < _STATUS_DETECTED:
       self._tool_prefix_status = _STATUS_DETECTED
       self._tool_prefix = self._DetectToolPrefix() or ''
       logging.debug('Detected --tool-prefix=%s', self._tool_prefix)
     return self._tool_prefix
@@ skipping 24 matching lines @@
         full_path = distutils.spawn.find_executable(tool_prefix + 'c++filt')
       else:
         full_path = tool_prefix + 'c++filt'
 
       if not full_path or not os.path.isfile(full_path):
         raise Exception('Bad --tool-prefix. Path not found: %s' % full_path)
       logging.info('Using --tool-prefix=%s', self._tool_prefix)
     return tool_prefix
 
   def _DetectOutputDirectory(self):
-    # See if input file is in out/Release.
-    abs_path = os.path.abspath(self._input_file)
-    release_idx = abs_path.find('Release')
-    if release_idx != -1:
-      output_directory = abs_path[:release_idx] + 'Release'
-      output_directory = os.path.relpath(abs_path[:release_idx] + '/Release')
-      return output_directory
+    # Try and find build.ninja.
+    abs_path = os.path.abspath(self._any_path_within_output_directory)
+    while True:
+      if os.path.exists(os.path.join(abs_path, 'build.ninja')):
+        return os.path.relpath(abs_path)
+      parent_dir = os.path.dirname(abs_path)
+      if parent_dir == abs_path:
+        break
+      abs_path = abs_path = parent_dir
 
     # See if CWD=output directory.
     if os.path.exists('build.ninja'):
       return '.'
     return None
 
   def _DetectToolPrefix(self):
     output_directory = self.output_directory
     if output_directory:
       # Auto-detect from build_vars.txt
       build_vars_path = os.path.join(output_directory, 'build_vars.txt')
       if os.path.exists(build_vars_path):
         with open(build_vars_path) as f:
           build_vars = dict(l.rstrip().split('=', 1) for l in f if '=' in l)
         return os.path.normpath(
             os.path.join(output_directory, build_vars['android_tool_prefix']))
     return None